Sticker



FIG. 1 is a front view of a sticker in accordance with a first embodiment of the design;

FIG. 2 is a rear view of the sticker illustrated in FIG. 1;

FIG. 3 is a front view of a sticker in accordance with a second embodiment of the design; and,

FIG. 4 is a rear view of the sticker illustrated in FIG. 3.

In the drawings, the broken lines represent features that form no part of the claimed design. 

The ornamental design for a sticker, as shown and described. 